U.S. patent application number 14/603618 was filed with the patent office on 2015-07-09 for method and apparatus for identifying channel information in a wireless network.
The applicant listed for this patent is LG ELECTRONICS INC.. Invention is credited to Inhwan CHOI, Kyoungsuk KO, Kyungchul KWAK, Hangseok OH, Jaehyung SONG.
Application Number | 20150195794 14/603618 |
Document ID | / |
Family ID | 45371936 |
Filed Date | 2015-07-09 |
United States Patent
Application |
20150195794 |
Kind Code |
A1 |
SONG; Jaehyung ; et
al. |
July 9, 2015 |
METHOD AND APPARATUS FOR IDENTIFYING CHANNEL INFORMATION IN A
WIRELESS NETWORK
Abstract
A method for transmitting and receiving, by a station, channel
information in a wireless LAN system, the method comprising:
receiving a beacon frame including the channel information, wherein
the channel information includes information for a channel change,
the information for the channel change includes a field for a
operating class of a new channel, a field for a channel number of
the new channel and a field for a maximum transmit power of the new
channel; parsing the beacon frame; and changing to a new channel
with the maximum transmit power.
Inventors: |
SONG; Jaehyung; (Seoul,
KR) ; OH; Hangseok; (Seoul, KR) ; KO;
Kyoungsuk; (Seoul, KR) ; KWAK; Kyungchul;
(Seoul, KR) ; CHOI; Inhwan; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG ELECTRONICS INC. |
Seoul |
|
KR |
|
|
Family ID: |
45371936 |
Appl. No.: |
14/603618 |
Filed: |
January 23, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13703825 |
Dec 12, 2012 |
9014164 |
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PCT/KR2011/004496 |
Jun 20, 2011 |
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14603618 |
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61356645 |
Jun 20, 2010 |
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61358933 |
Jun 27, 2010 |
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61361436 |
Jul 5, 2010 |
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Current U.S.
Class: |
370/329 |
Current CPC
Class: |
H04N 21/00 20130101;
H04W 72/0473 20130101; H04W 52/30 20130101; H04W 52/54 20130101;
H04W 84/12 20130101; H04W 16/14 20130101; H04W 52/367 20130101;
H04W 72/0453 20130101; H04W 88/08 20130101 |
International
Class: |
H04W 52/30 20060101
H04W052/30; H04W 72/04 20060101 H04W072/04 |
Claims
1-16. (canceled)
17. A method for providing, by a first station, channel information
in a wireless local area network system, the method comprising:
acquiring, by the first station, the channel information by
accessing a geo-location database; and transmitting, by the first
station to a second station, a frame including at least one
triplet, wherein the triplet includes an operating class field, a
channel number field, and a maximum transmit power field, wherein
the operating class field and the channel number field together
specify at least one channel on which the second station is allowed
to operate based on a maximum allowable transmission power
indicated by the maximum transmit power field, and wherein the
operating class field indicates at least a channel set for which
the channel information applies.
18. The method according to claim 17, wherein the first station is
an enabling station and the second station is a dependent
station.
19. The method according to claim 17, wherein the frame including
the at least one triplet is transmitted in response to a request
frame.
20. The method according to claim 17, wherein the operating class
field represents an index for a set of values of information
including channel starting frequency, channel spacing, the channel
set, and behavior limits set.
21. The method according to claim 17, wherein the first station and
the second station operate in a TV white space band.
22. The method according to claim 17, wherein one of the at least
one triplet is a set of three field, each of three fields has one
octet length.
23. The method according to claim 17, wherein the at least one
triplet is transmitted in a registered location query protocol
element.
24. The method according to claim 17, wherein the frame including
the at least one triplet is a public action frame.
25. A first station for providing channel information in a wireless
local area network system, the station comprising: a
transmitting/receiving unit; and a control unit, wherein the
control unit is configured to: acquire the channel information by
accessing a geo-location database; and control the
transmitting/receiving unit to transmit, to a second station, a
frame including at least one triplet, wherein the triplet includes
an operating class field, a channel number field, and a maximum
transmit power field, wherein the operating class field and the
channel number field together specify at least one channel on which
the second station is allowed to operate based on a maximum
allowable transmission power indicated by the maximum transmit
power field, and wherein the operating class field indicates at
least a channel set for which the channel information applies.
Description
BACKGROUND
[0001] The present disclosure relates to a wireless LAN system
using TV white space, and more particularly, to a device and method
for identifying channel information in a wireless network.
[0002] A television broadcast service is currently shifting from
analog to digital broadcasting, since the digital broadcasting can
provide high quality images and interactive services and enable
more efficient use of spectrums.
[0003] The shifting to digital broadcasting allows a part of a very
high frequency (VHF, 54 MHz to 88 MHz) band and ultra high
frequency (UHF, 174 MHz to 698 MHz) band, allocated for typical
analog broadcasting, to be used by anybody. One of examples of such
an available frequency band is TV white space (hereinafter,
referred to as `TVWS`).
[0004] That is, the TVWS means a VHF or UHF frequency band which is
allocated for TV broadcasting but is not used by a broadcast
provider. Thus, the TVWS is an unlicensed frequency band which can
be used by anybody when radio regulations of the government are
satisfied. When a licensed device is not used in the unlicensed
frequency band, an unlicensed device may use the frequency band.
Here, the licensed device means a user permitted to use the TVWS,
and may be called a primary user (or TV signal) or incumbent
user.
[0005] The Federal Communications Commission (FCC) of the United
States allowed a VHF frequency band and UHF frequency band used for
a DTV to be used by anybody satisfying the regulations provided by
the FCC.
[0006] For example, as illustrated in FIG. 1, the FCC is preparing
a regulation for allowing unlicensed devices to use TV channels
other than channel 37 (reserved for radio astronomy) when signals
such as TV signals and wireless microphone signals of licensed
devices do not exist in the TV channels. By applying such a
regulation of the FCC with modifications, other countries are
preparing policies and regulations with respect to the TVWS.
[0007] Further, various wireless communication systems for using
the TVWS is being developed. For example, the Institute of
Electrical and Electronics Engineers (IEEE) 802.11 working group is
developing a wireless local area network (WLAN) system using the
TVWS with the 802.11af standard.
SUMMARY
[0008] Embodiments provide an information element and a public
action frame for enabling wireless LAN devices operating in TVWS to
identify channel information.
[0009] Embodiments also provide a method and device for enabling
wireless LAN devices operating in TVWS to identify a power change
of an operating channel.
[0010] Embodiments also provide a method and device for enabling
wireless LAN devices operating in TVWS to identify information on a
channel to move to.
[0011] Embodiments also provide a method and device for enabling
wireless LAN devices operating in TVWS to perform a deenablement
operation to a specific channel.
[0012] In one embodiment, A method for transmitting and receiving,
by a station, channel information in a wireless LAN system, the
method comprising: receiving a beacon frame including the channel
information, wherein the channel information includes information
for a channel change, the information for the channel change
includes a field for a operating class of a new channel, a field
for a channel number of the new channel and a field for a maximum
transmit power of the new channel; parsing the beacon frame; and
changing to a new channel with the maximum transmit power.
[0013] In another embodiment, A device for transmitting and
receiving, by a station, channel information in a wireless LAN
system, the device comprising: an RF transmitting/receiving unit
configured to receive a beacon frame including the channel
information, wherein the channel information includes information
for a channel change, the information for the channel change
includes a field for a operating class of a new channel, a field
for a channel number of the new channel and a field for a maximum
transmit power of the new channel; and a control unit configured to
parse the beacon frame and change to a new channel with the maximum
transmit power.
[0014] According to an embodiment, wireless LAN devices operating
in the TVWS are enabled to identify available maximum transmit
power according to whether a TV broadcasting service exists in an
adjacent channel, and thus communication can be performed without
interference on the TV broadcasting service existing in the
adjacent channel.
[0015] According to another embodiment, an enabling STA operating
in the TVWS can perform deenablement to a dependent STA operating
in a specific channel.
[0016] Other various effects will be explicitly or implicitly
disclosed in the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 illustrates a channel map showing a TV band of the US
and a band where W-LAN devices can operate.
[0018] FIG. 2 illustrates two methods for defining a channel in a
wireless LAN system using the TVWS.
[0019] FIG. 3 illustrates an example of maximum transmit power
limited according to whether a primary user exists in an adjacent
channel in the TVWS and to a type of the primary user.
[0020] FIG. 4 illustrates a TV signal of an adjacent channel, which
exists or not according to a channel defining method of the
wireless LAN system, and maximum transmit power depending on
whether the TV signal exists or not.
[0021] FIG. 5 illustrates a structure of a channel power management
announcement element according to a first embodiment.
[0022] FIG. 6 illustrates a structure of a registered location
query protocol element according to the first embodiment.
[0023] FIG. 7 illustrates a structure of a channel power management
announcement frame according to the first embodiment.
[0024] FIGS. 8 to 11 illustrate an example of performing power
switch by devices belonging to a wireless network.
[0025] FIGS. 12 to 15 illustrate an example of performing channel
switch by devices belonging to a wireless network.
[0026] FIG. 16 illustrates a process flow of performing power
switch or channel switch by devices belonging to a wireless network
by using an information element or frame according to the first
embodiment.
[0027] FIG. 17 illustrates an example of performing enablement by
an enabling STA and a dependent STA operating in the TVWS.
[0028] FIG. 18 illustrates an example of performing deenablement by
the enabling STA and dependent STA of FIG. 17.
[0029] FIG. 19 illustrates a structure of the DSE deenablement
public action frame defined in the IEEE 802.11y standard.
[0030] FIG. 20 illustrates a structure of a DSE extended
deenablement frame according to a second embodiment.
[0031] FIG. 21 illustrates another example of performing
deenablement by the enabling STA and dependent STA of FIG. 17.
[0032] FIG. 22 is a flowchart illustrating a process of performing
deenablement by using the DSE extended deenablement frame according
to the second embodiment.
[0033] FIG. 23 is a block diagram illustrating wireless LAN devices
in which the embodiments may be implemented.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0034] Detailed descriptions of well-known functions or
configurations will be omitted in order not to unnecessarily
obscure the focus of the present invention. The terms used herein
are defined in consideration of functions of the present invention,
but may be differently defined according to intention of a user or
operator. Thus, the definitions should be determined based on the
overall content of the present disclosure.
[0035] A wireless LAN system performs communication by using a
channel bandwidth of 5 MHz, 10 MHz, 20 MHz, or 40 MHz in a 2.4 GHz
or 5 GHz band. On the contrary, channel bandwidths of TV white
space (TVWS) are different according to regions and/or nations, and
thus 6 MHz, 7 MHz, or 8 MHz may be used depending on regions. Since
a channel allocation unit of the wireless LAN system is different
from that of the TVWS, it is needed to define a corresponding
channel according to the channel bandwidth of the TVWS for the
wireless LAN system using the TVWS.
[0036] For example, FIG. 2 illustrates two methods for defining a
corresponding channel (5 MHz, 10 MHz, 20 MHz, or 40 MHz) of the
wireless LAN system in a TVWS band where a channel is allocated in
a unit of 6 MHz.
[0037] Referring to FIG. 2(A), according to a first channel
defining method (Channelization A), for each channel (5/10/20/40
MHz) of the wireless LAN system, a center frequency corresponding
channel is located at a center frequency of a TV channel (6
MHz).
[0038] Referring to FIG. 2(B), according to a second channel
defining method (Channelization B), for each channel (5/10/20/40
MHz) of the wireless LAN system, a center frequency of a
corresponding channel is located at a boundary between contiguous
two TV channel bands.
[0039] The wireless LAN system using the TVWS may perform
communication by using one of the above-described two channel
defining methods.
[0040] According to the regulations of the Federal Communications
Commission (FCC) of the United States, when a TV signal (or TV
broadcast) does not exist in a channel adjacent to an operating
channel in a wireless network using the TVWS, wireless LAN devices
belonging to a corresponding network may operate with maximum
transmit power of 100 mW. On the contrary, when a TV signal exists
in the adjacent channel, the wireless LAN devices belonging to a
corresponding network may operate with maximum transmit power of 40
mW.
[0041] That is, when a primary user exists in the adjacent channel,
maximum transmit power of the wireless LAN devices is limited in
order to prevent inference on the primary user.
[0042] For example, FIG. 3 illustrates an example of maximum
transmit power limited according to whether a primary user exists
in an adjacent channel in the TVWS and to a type of the primary
user.
[0043] Referring to FIG. 3, when an operating channel is channel
22, since a primary user does not exist in channels 21 and 23
adjacent to the channel 22, the wireless LAN devices operating in
the channel 22 may transmit signals with maximum transmit power of
100 mW.
[0044] When the operating channel is the channel 21 or 23, since a
primary user, i.e. a "TV signal", exists in an adjacent channel to
the operating channel, maximum transmit power of the wireless LAN
devices operating in the channel 21 or 23 is limited to 40 mW.
[0045] When the operating channel is channel 40, a primary user
exists in channels 39 and 41 adjacent to the operating channel.
However, when a type of the primary user is not a "TV signal" but a
"wireless microphone (W-MIX) signal", the wireless LAN devices may
transmit signals with maximum transmit power of not 40 mW but 100
mW.
[0046] In FIG. 3, the wireless microphone signal is allocated to
the channels 39 and 41 but is not limited thereto. That is,
according to changes in the regulations of the FCC, the wireless
microphone signal may be allocated to other channels.
[0047] In addition, although it is exemplified that the wireless
LAN devices operate with maximum transmit power of 100 mW or 40 mW
according to whether a TV signal exists in an adjacent channel, the
numerical values may also be changed according to the changes in
the regulations of the FCC.
[0048] FIG. 4 illustrates a TV signal of an adjacent channel, which
exists or not according to channel definitions of the wireless LAN
system, and maximum transmit power depending on whether the TV
signal exists or not. In FIG. 4(A), the wireless LAN system defines
a corresponding channel by using the first channel defining method
of FIG. 2. In FIG. 4(B), the wireless LAN system defines a
corresponding channel by using the second defining method of FIG.
2.
[0049] Referring to FIGS. 4(A) and 4(B), TV signals exist in
channels 27 and 33, and channels 28 to 32 are empty. In this state,
the wireless LAN system needs to define a channel of 5 MHz, 10 MHz,
20 MHz, or 40 MHz in order to use empty TVWS channels.
[0050] Firstly, when the wireless LAN system defines a channel of 5
MHz or 10 MHz, it may be confirmed that a TV signal does not exist
in an adjacent channel to the defined channel regardless of the
above-described channel defining methods. Therefore, the wireless
LAN system operating in a kth channel by using the channel
bandwidth of 5 MHz or 10 MHz may transmit signals with maximum
transmit power of 100 mW.
[0051] When the wireless LAN system defines a channel of 20 MHz, it
may be confirmed that a TV signal exists in an adjacent channel to
the defined channel regardless of the above-described channel
defining methods. Therefore, the maximum transmit power of the
wireless LAN system operating in the kth channel by using the
channel bandwidth of 20 MHz is limited to 40 mW.
[0052] That is, as illustrated in FIG. 4, even though a channel of
the wireless LAN system shares a TVWS band, a TV signal may exist
or may not exist in an adjacent channel according to a bandwidth of
the channel of the wireless LAN system. Further, according to
whether the TV signal exists in the adjacent channel, the maximum
transmit power of the channel of the wireless LAN system is
changed.
[0053] Therefore, the wireless LAN device operating in the TVWS
should recognize the maximum transmit power of a channel where the
device is operating or a channel to which the device desires to
move. While the wireless LAN device operates in the TVWS, if a fact
on whether the TV signal exists in the adjacent channel is changed,
it is needed to change the maximum transmit power.
[0054] However, the IEEE 802.11af standard does not provide a
method for enabling the wireless LAN device to identify the maximum
transmit power of a corresponding channel.
[0055] Therefore, a first embodiment provides an information
element and a frame for enabling the wireless LAN devices operating
in the TVWS to identify channel information of a corresponding
channel.
[0056] Further, the first embodiment provides a method for enabling
the wireless LAN devices to identify information on maximum
transmit power of an operating channel or a channel to move to by
using the information element or frame.
First Embodiment
[0057] Hereinafter, the first embodiment will be described in
detail with reference to the accompanying drawings.
[0058] FIG. 5 illustrates a channel power management announcement
element 500 for announcing channel information. Here, the channel
power management announcement element 500 may be referred to as a
channel power switch announcement element.
[0059] The information element 500 may be used for signaling
channel information that is dynamically changed. For example, when
information on an available channel list is changed in a wireless
network, the information element 500 may be used for announcing the
changed available channel list information.
[0060] Further, when an operating channel in the wireless network
is changed from a current channel to a new channel or the maximum
transmit power defined for a currently operating channel is
changed, the information element 500 may be used for signaling the
changed channel information.
[0061] The information element 500 may be included in a beacon
frame, a probe response frame, an association response frame, or a
reassociation response frame in order to be transmitted.
[0062] Here, the beacon frame is a signal periodically transmitted
by an access point (hereinafter, referred to as an AP) in order to
transmit system information and/or state information of the
wireless network to stations that belong thereto.
[0063] The probe response frame is a signal transmitted by the AP
in response to a probe request frame that is transmitted from a
station belonging to the wireless network to request information on
the network.
[0064] The association response frame or reassociation response
frame is a signal transmitted by the AP in response to an
association request frame or reassociation request frame that is
transmitted from a station belonging to the wireless network to
request association to the network.
[0065] Management frames such as the beacon frame and probe
response frame may announce that an information element about
channel power management is included in a frame body.
[0066] For example, as shown in Table 1 below, the beacon frame may
announce that the information element about the channel power
management is included, by using information number 36 of a frame
body.
TABLE-US-00001 TABLE 1 Order Information Notes 36 Supported The
Supported Operating Classes Operating element is present if Classes
dot11ExtendedChannelSwitchActivated or
dot11ChannelPowerManagementActivated is true.
[0067] Further, as shown in Table 2 below, the beacon frame may
announce that the information element about the channel power
management is included, by defining additional order information in
a frame body.
TABLE-US-00002 TABLE 2 Order Information Notes <ANA> Channel
Power Channel Power Management Management Announcement element is
optionally Announcement present if
dot11ChannelPowerManagementActivated is true.
[0068] Further, as shown in Table 3 below, the association request
frame may announce that the information element about the channel
power management is included, by using information numbers 7 and 12
of a frame body.
TABLE-US-00003 TABLE 3 Order Information Notes 7 Supported The
Supported Channels element Channels shall be present if
dot11SpectrumManagementRequired is true and either
dot11ExtendedChannelSwitchActivated is false or
dot11ChannelPowerManagementActivated is true. 12 Supported The
Supported Operating Classes Operating information element is
present if Classes dot11ExtendedChannelSwitchEnabled or
dot11ChannelPowerManagementActivated is true.
[0069] Further, as shown in Table 4 below, the reassociation
request frame may announce that the information element about the
channel power management is included, by using information numbers
8 and 15 of a frame body.
TABLE-US-00004 TABLE 4 Order Information Notes 8 Supported The
Supported Channels element Channels shall be present if
dot11SpectrumManagementRequired is true and either
dot11ExtendedChannelSwitchActivated is false or
dot11ChannelPowerManagementActivated is true. 15 Supported The
Supported Operating Classes Operating information element is
present if Classes dot11ExtendedChannelSwitchActivated or
dot11ChannelPowerManagementActivated is true.
[0070] Further, as shown in Table 5 below, the probe request frame
may announce that the information element about the channel power
management is included, by using information number 6 of a frame
body.
TABLE-US-00005 TABLE 5 Order Information Notes 6 Supported The
Supported Operating Classes Operating information element is
present if Classes dot11ExtendedChannelSwitchActivated or
dot11ChannelPowerManagementActivated is true.
[0071] Further, as shown in Table 6 below, the probe response frame
may announce that the information element about the channel power
management is included, by defining additional order information in
a frame body.
TABLE-US-00006 TABLE 6 Order Information Notes <ANA> Channel
Power The Channel Power Management Management Announcement element
is optionally Announcement present if
dot11ChannelPowerManagementActivated is true.
[0072] An AP constituting a basic service set (BSS) and a station
constituting an independent basic service set (IBSS) may transmit
the beacon frame, probe response frame, or association response
frame including the information element 500 to other stations in
order to announce changed channel information.
[0073] Referring to FIG. 5, the information element 500 includes an
element ID field 510, a length field 520, a channel power
management mode field 530, a channel power switch count field 540,
an operating class field 550, a channel number field 560, and a
regulatory maximum transmit power/local power constraint field
570.
[0074] The element ID field 510 represents an identifier (ID) of
the corresponding information element, and the length field 520
represents a length of the corresponding information element. Here,
a value of the length field 520 may be variable, and a minimum
value thereof is 3.
[0075] The channel power management mode field 530 includes channel
information to be announced through the information element 500.
That is, the channel power management mode field 530 performs
signaling to indicate whether a role of the information element 500
is to change transmit power on an operating channel or to switch
between channels.
[0076] More specifically, the channel power management mode field
530 indicates whether the information element 500 is used for
announcing a change in the available channel list, is used for
announcing switching to a new channel and announcing the regulatory
maximum transmit power (or local power constraint) in the new
channel, or is used for announcing a change in the regulatory
maximum transmit power (or local power constraint) in an operating
channel without channel switching.
[0077] Further, the channel power management mode field 530
indicates whether the information element 500 includes the channel
power switch count field 540 or regulatory maximum transmit
power/local power constraint field 570.
[0078] Further, the channel power management mode field 530
indicates whether the information element 500 includes a triplet
consisting an operating class, a channel number, and regulatory
maximum transmit power or a triple consisting of an operating
class, a channel power, and local power constraint.
[0079] Further, the channel power management mode field 530
indicates several constraints on transmission until channel
switching or power switching is completed.
[0080] In order to announce the above-described different pieces of
channel information, the channel power management mode field 530
defines values as shown in Table 7 below.
TABLE-US-00007 TABLE 7 Channel Power Management Mode Value
Description 0 A channel power management announcement element does
not include a channel power switch count field. The channel power
management announcement element includes a triplet consisting of an
operating class, a channel number, and regulatory maximum transmit
power. The channel power management announcement element is used
for announcing addition of new channel(s) to the available channel
list. 1 The channel power management announcement element does not
include the channel power switch count field. The channel power
management announcement element includes an operating class field
and a channel number field, and does not include a regulatory
maximum transmit power/local power constraint field. The channel
power management announcement element is used for announcing
deletion of new channel(s) from the available channel list. 2 The
channel power management announcement element includes the channel
power switch count field. The channel power management announcement
element includes a triplet consisting of an operating class, a
channel number, and regulatory maximum transmit power. The channel
power management announcement element is used for announcing a
change in regulatory maximum transmit power for a specific channel
without channel switching. Transmission interruption is not
requested until the changing the regulatory maximum transmit power
is completed. 3 The channel power management announcement element
includes the channel power switch count field. The channel power
management announcement element includes a triplet consisting of an
operating class, a channel number, and regulatory maximum transmit
power. The channel power management announcement element is used
for announcing a change in regulatory maximum transmit power for a
specific channel without channel switching. Transmission
interruption is requested until the changing the regulatory maximum
transmit power is completed. 4 The channel power management
announcement element includes the channel power switch count field.
The channel power management announcement element includes a
triplet consisting of an operating class, a channel number, and
regulatory maximum transmit power. The channel power management
announcement element is used for announcing switching to new
channel(s) having the regulatory maximum transmit power.
Transmission interruption is not requested until the channel
switching is completed. 5 The channel power management announcement
element includes the channel power switch count field. The channel
power management announcement element includes a triplet consisting
of an operating class, a channel number, and regulatory maximum
transmit power. The channel power management announcement element
is used for announcing switching to new channel(s) having the
regulatory maximum transmit power. Transmission interruption is
requested until the channel switching is completed. 6 The channel
power management announcement element includes the channel power
switch count field. The channel power management announcement
element includes a triplet consisting of an operating class, a
channel number, and local power constraint. The channel power
management announcement element is used for announcing a change in
local power constraint for a specific channel without channel
switching. Transmission interruption is not requested until the
changing the local power constraint is completed. 7 The channel
power management announcement element includes the channel power
switch count field. The channel power management announcement
element includes a triplet consisting of an operating class, a
channel number, and local power constraint. The channel power
management announcement element is used for announcing a change in
local power constraint for a specific channel without channel
switching. Transmission interruption is requested until the
changing the local power constraint is completed. 8 The channel
power management announcement element includes the channel power
switch count field. The channel power management announcement
element includes a triplet consisting of an operating class, a
channel number, and local power constraint. The channel power
management announcement element is used for announcing switching to
new channel(s) having the local power constraint. Transmission
interruption is not requested until the channel switching is
completed. 9 The channel power management announcement element
includes the channel power switch count field. The channel power
management announcement element includes a triplet consisting of an
operating class, a channel number, and local power constraint. The
channel power management announcement element is used for
announcing switching to new channel(s) having the local power
constraint. Transmission interruption is requested until the
channel switching is completed. 10 The channel power management
announcement element does not include the channel power switch
count field. The channel power management announcement element
includes a triplet consisting of an operating class, a channel
number, and regulatory maximum transmit power. The channel power
management announcement element is used for deenabling a specific
channel. 11-255 Reserved
[0081] Referring to Table 7, the channel power management mode
field 530 defines 11 (0 to 10) mode values.
[0082] When a mode value of the channel power management mode field
530 is `0`, the value means that the information element 500 is
used for announcing addition of new channel(s) to the available
channel list. Here, the information element 500 includes
information on an operating class, a channel number, and regulatory
maximum transmit power for the newly added channel(s).
[0083] When the mode value of the channel power management mode
field 530 is `1`, the value means that the information element 500
is used for announcing deletion of existing channel(s) from the
available channel list. Here, the information element 500 includes
information on an operating class and a channel number for the
deleted channel(s). In addition, the information element 500 does
not include information on regulatory maximum transmit power/local
power constraint for the deleted channels.
[0084] When the mode value of the channel power management mode
field 530 is `2` or `3`, the value means that the information
element 500 is used for announcing a change in regulatory maximum
transmit power in a specific channel without channel switching.
Here, the information element 500 includes information on an
operating class, a channel number, and regulatory maximum transmit
power of the specific channel.
[0085] Further, the information element 500 includes information on
whether transmission is interrupted until changing the regulatory
maximum transmit power is completed. Here, when the mode value is
`2`, the interruption of data transmission is not requested until
the power changing is completed. On the contrary, when the mode
value is `3`, the interruption of data transmission is requested
until the power changing is completed.
[0086] When the mode value of the channel power management mode
field 530 is `4` or `5`, the value means that the information
element 500 is used for announcing switching to new channel(s)
having the regulatory maximum transmit power. Here, the information
element 500 includes information on an operating class, a channel
number, and the regulatory maximum transmit power of the new
channel(s).
[0087] Further, the information element 500 includes information on
whether transmission is interrupted until the channel switching is
completed. Here, when the mode value is `4`, the interruption of
data transmission is not requested until the channel switching is
completed. On the contrary, when the mode value is `5`, the
interruption of data transmission is requested until the channel
switching is completed.
[0088] When the mode value of the channel power management mode
field 530 is `6` or `7`, the value means that the information
element 500 is used for announcing a change in local power
constraint in a specific channel without channel switching. Here,
the information element 500 includes information on an operating
class, a channel number, and the local power constraint of the
specific channel.
[0089] Further, the information element 500 includes information on
whether transmission is interrupted until the changing the local
power constraint is completed. Here, when the mode value is `6`,
the interruption of data transmission is not requested until the
power changing is completed. On the contrary, when the mode value
is `7`, the interruption of data transmission is requested until
the power changing is completed.
[0090] When the mode value of the channel power management mode
field 530 is `8` or `9`, the value means that the information
element 500 is used for announcing switching to new channel(s)
having the local power constraint. Here, the information element
500 includes information on an operating class, a channel number,
and the local power constraint of the new channel(s).
[0091] Further, the information element 500 includes information on
whether transmission is interrupted until the channel switching is
completed. Here, when the mode value is `8`, the interruption of
data transmission is not requested until the channel switching is
completed. On the contrary, when the mode value is `9`, the
interruption of data transmission is requested until the channel
switching is completed.
[0092] When the mode value of the channel power management mode
field 530 is `10`, the value means that the information element 500
is used for announcing deenablement of a specific channel. Here,
the information element 500 includes information on an operating
class, a channel number, and regulatory maximum transmit power of
the specific channel. For example, the information element 500 may
set the regulatory maximum transmit power to `0`.
[0093] Referring to FIG. 5, the channel power switch count field
540 indicates the number of target beacon transmission times
(TBTTs) until a station transmitting the information element 500
switches to a new channel, or indicates a zero value.
[0094] For example, when a value of the channel power switch count
field 540 is set to `1`, this value means that channel switching
instantly occurs before next TBTT.
[0095] When the value of the channel power switch count field 540
is set to `0`, this value means that channel switching may occur at
any time after a frame including the information element 500 is
transmitted. Further, in the case of changing the regulatory
maximum transmit power in an operating channel without channel
switching, the same zero value may be set.
[0096] The operating class field 550 indicates a number of an
operating class of a corresponding channel. Here, the operating
class represents an index for a set of values for wireless
operations in the wireless LAN system. Here, the values for
wireless operations include a channel starting frequency, channel
spacing, a channel set, and a behavior limit set.
[0097] The channel number field 560 indicates a number of a
corresponding channel. Here, the number of the corresponding
channel is defined in an operating class of a station.
[0098] The regulatory maximum transmit power/local power constraint
field 570 indicates available transmit power in a specific channel
after channel power management (channel or power switching).
[0099] The regulatory maximum transmit power 570 represents the
maximum transmit power defined by an organization such as the FCC
to prevent interference on a primary user (TV signal). For example,
according to whether a TV signal exists in an adjacent channel, the
regulatory maximum transmit power may define the available maximum
transmit power as 100 mW or 40 mW, but is not limited thereto.
[0100] The local power constraint field 570 represents that an AP
limits transmit power of stations managed thereby in order to
prevent interference between stations. That is, the local power
constraint does not represent regulatory transmit power constraint,
but represents the transmit power constraint determined by the AP.
The local power constraint field 570 is not necessarily included in
the information element 500 but may be selectively included.
[0101] The operating class field 550, the channel number field 560,
and the regulatory maximum transmit power/local power constraint
field 570 constitute one triplet 680, wherein the triplet 680 may
be repeated by as much as the length specified in the length field
520.
[0102] FIG. 6 illustrates a registered location query protocol
element 600 for announcing channel information.
[0103] The information element 600 may be used for signaling
channel information that is dynamically changed. In particular, the
information element 600 may be used to request channel power
management or respond thereto by using the GAS protocol defined in
the IEEE 802.11u standard rather than using a designated public
action frame.
[0104] Referring to FIG. 6, the information element 600 includes an
information ID field 610, a length field 620, and a channel power
management announcement field 630.
[0105] The information ID field 610 indicates that the
corresponding information element is related to channel power
management.
[0106] The length field 620 indicates a length of the channel power
management announcement field 630. Here, a value of the length
field 620 may be variable, and a minimum value thereof is 3.
[0107] The channel power management announcement field 630
indicates information on the channel power management announcement
element 500. That is, the channel power management announcement
field 630 may have the same configuration as the fields included in
the channel power management announcement element 500.
[0108] FIG. 7 illustrates a channel power management announcement
frame 700 for announcing channel information. Here, the channel
power management announcement frame may be referred to as a channel
power switch announcement frame.
[0109] The channel power management announcement frame 700 is a
kind of a public action frame. That is, the channel management
announcement frame 700 is transmitted as an additional frame, not
being included in the beacon frame or probe response frame in order
to be transmitted like the above-described channel power management
element 500.
[0110] The frame 700 may be used for signaling channel information
that is dynamically changed. For example, when information on the
available channel list is changed in the wireless network, the
frame 700 may be used for announcing the changed available channel
list information.
[0111] Further, when an operating channel in the wireless network
is changed from a current channel to a new channel or the maximum
transmit power defined for a currently operating channel is
changed, the frame 700 may be used for signaling the changed
channel information.
[0112] Referring to FIG. 7, the frame 700 includes a category field
710, an action value field 720, a length field 730, a channel power
switch mode field 740, a channel power switch count field 750, an
operating class field 760, a channel number field 770, and a
regulatory maximum transmit power/local power constraint field
780.
[0113] The category field 710 represents a category of the
corresponding frame, and the action value field 720 represents that
the corresponding frame is the channel power management
announcement frame.
[0114] The length field 730, the channel power switch mode field
740, the channel power switch count field 750, the operating class
field 760, the channel number field 770, and the regulatory maximum
transmit power/local power constraint field 780 may have the same
configurations as the fields included in the channel power
management announcement element 500 of FIG. 5. Therefore,
descriptions of the length field 730, the channel power switch mode
field 740, the channel power switch count field 750, the operating
class field 760, the channel number field 770, and the regulatory
maximum transmit power/local power constraint field 780 included in
the frame 700 are not provided.
[0115] Further, a protected dual of public action frame may be
defined as shown in Table 8 below.
TABLE-US-00008 TABLE 8 Action Field value Description <ANA>
Protected Channel Power Management Announcement
[0116] That is, when management frame protection is negotiated, a
protected channel power management announcement frame may be used
instead of the channel power management announcement frame 700.
Here, the protected channel power management announcement frame has
the same configuration as the channel power management announcement
frame 700. Further, the protected channel power management
announcement frame may include information on an encryption key for
decrypting payload information.
[0117] Hereinafter, a method for enabling the wireless LAN devices
to identify information on maximum transmit power of an operating
channel or a channel to move to by using the above-described
information element or frame will be described.
[0118] FIGS. 8 to 11 illustrate an example of performing power
switching in an operating channel by devices belonging to the
wireless network by using the information element or frame
according to the present invention.
[0119] Referring to FIGS. 8 to 11, the wireless LAN system includes
at least one basic service set (BSS) 810 and a distribution system
(DS, not illustrated).
[0120] The BSS is a set of terminals capable of performing
communication with successful synchronization, and does not
indicate a specific region.
[0121] The distribution system is a mechanism for communication
between terminals, and is not necessarily a network. If the
distribution system is capable of providing the distribution
service defined in the IEEE 802.11 standard, a form of the
distribution system is not limited. For example, the distribution
system may be a wireless network such as a mesh network or a
physical structure for interconnecting APs.
[0122] The BSS 810 may include an AP 801 for controlling a
corresponding wireless network and stations 803, 805, and 807
associated with the AP 801 to operate. Here, it is assumed that the
AP 801 and the stations 803, 805, and 807 in the BSS 810 are
terminals that may use the TVWS.
[0123] The AP 801 is a functional medium that enables access to the
distribution system via a wireless medium, for the stations 803,
805, and 807 associated with the corresponding wireless network.
Further, the AP 801 serves to manage and control the stations 803,
805, and 807 belonging to the corresponding wireless network.
[0124] The AP 801 may also be referred to as a centralized
controller, a base station (BS), node-B, a base transceiver system
(BTS), or a site controller. In addition, the stations 803, 805,
and 807 may also be referred to as terminals, wireless
transmit/receive units (WTRUs), user equipments (UEs), mobile
stations (MSs), mobile terminals, or mobile subscriber units.
[0125] Referring to FIG. 8, the AP 801 and the stations 803, 805,
and 807 in the wireless network 810 perform communication by using
channel 22 of a TVWS channel map 820. Here, since a TV signal does
not exist in channels 21 and 23 adjacent to the channel 22, the AP
801 and the stations 803, 805, and 807 belonging to the network 810
may perform communication with maximum transmit power of 100
mW.
[0126] Referring to FIG. 9, while the devices belonging to the
wireless network 810 perform communication by using the channel 22,
a TV broadcasting station initiates TV broadcasting by using the
channel 21 adjacent to the channel 22.
[0127] Here, the AP 801 may recognize the existence of the TV
signal in the adjacent channel by periodically accessing a
geo-location database and updating obtained available channel list
information.
[0128] Further, the AP 801 may recognize the existence of the TV
signal on the basis of spectrum sensing results reported from the
stations 803, 805, and 807 managed by the AP 801. Here, the
spectrum sensing is performed by the wireless LAN devices in the
wireless network using the TVWS to detect whether a licensed device
(or primary user) exits within the coverage of the network.
[0129] Since the TV signal is a licensed user, the network 810
needs to limit the maximum transmit power of the current channel to
40 mW so as to prevent interference on the TV signal existing in
the adjacent channel. In addition, although the TV signal is
described as a licensed user in the present embodiment, the
licensed user is not limited thereto.
[0130] Thereafter, referring to FIG. 10, the AP 801 transmits, to
the stations 803, 805, and 807 belonging to the network 810, a
frame 830 including the channel power management announcement
element 500. Here, the frame 830 may be the beacon frame, the probe
response frame, the association response frame, or the
reassociation response frame.
[0131] Further, the AP 801 may transmit, to the stations 803, 805,
and 807, an additional frame, i.e. the channel power management
announcement frame 700.
[0132] The frame 830 transmitted by the AP 801 includes information
for instructing the stations to decrease the regulatory maximum
transmit power of a currently operating channel from 100 mW to 40
mW. Further, the channel power management mode field 530, 740 of
the frame 830 includes a value set to `2` or `3`, and the
regulatory maximum transmit power field 570, 780 includes a value
set to 40 mW of the regulatory maximum transmit power.
[0133] Thereafter, referring to FIG. 11, the stations 803, 805, and
807 obtain information on a current channel by using the frame 830
received from the AP 801.
[0134] That is, the stations 803, 805, and 807 may identify not the
channel switching but the power switching in an operating channel
by analyzing the channel power management mode field of the
received frame 830. Further, the stations 803, 805, and 807 may
identify the available maximum transmit power in a currently
operating channel by analyzing the regulatory maximum transmit
power field.
[0135] When the receiving processes of the stations 803, 805, and
807 are completed, the AP 801 and the stations 803, 805, and 807
belonging to the wireless network start communication again in an
operating channel (channel 22) by using the maximum transmit power
of 40 mW.
[0136] FIGS. 12 to 15 illustrate an example of performing channel
switching by devices belonging to the wireless network by using the
information element or frame according to the present
invention.
[0137] Referring to FIG. 12, a wireless network (BSS) 1210 using
the TVWS includes one AP 1201 and first to third stations 1203,
1205, and 1207 associated with the AP 1201.
[0138] The AP 1201 and the first to third stations 1203, 1205, and
1207 existing in the wireless network 1210 perform communication by
using channel 22 of a TVWS channel map 1220. Here, since a TV
signal does not exist in channels 21 and 23 adjacent to the channel
22, the AP 1201 and the first to third stations 1203, 1205, and
1207 belonging to the network 1210 may perform communication with
maximum transmit power of 100 mW.
[0139] Referring to FIG. 13, while the devices belonging to the
wireless network 1210 perform communication by using the channel
22, a TV broadcasting station initiates TV broadcasting by using
the channel 22.
[0140] Here, the AP 1201 may recognize the appearance of the TV
signal 1230 in the current channel by periodically accessing the
geo-location database and updating available channel list
information. Further, the AP 1201 may recognize the appearance of
the TV signal 1230 by periodically performing spectrum sensing.
Further, the AP 1201 may also recognize the appearance of the TV
signal 1230 on the basis of spectrum sensing results reported from
the stations 1203, 1205, and 1207 managed by the AP 1201.
[0141] Since the TV signal 1230 is a licensed user, the network
1210 should move to another available channel. Although the TV
signal is described as a licensed user in the present embodiment,
the licensed user is not limited thereto.
[0142] Thereafter, referring to FIG. 14, it is assumed that the
network 1210 moves to a new channel, i.e. channel 21. Here,
referring to the channel map 1220, a TV signal does not exist in an
adjacent channel to the current channel (channel 22), but a TV
signal exists in an adjacent channel to the new channel 22.
Therefore, the maximum transmit power for the wireless LAN devices
desired to move to the channel 21 should be limited to 40 mW.
[0143] To this end, the AP 1201 transmits, to the stations 1203,
1205, and 1207 belonging to the network 1210, a frame 1240
including the channel power management announcement element 500.
Here, the frame 1240 may be the beacon frame, the probe response
frame, the association response frame, or the reassociation
response frame.
[0144] Further, the AP 1201 may transmit, to the stations 1203,
1205, and 1207, an additional frame, i.e. the channel power
management announcement frame 700, 1240.
[0145] The frame 1240 transmitted by the AP 1201 includes
information on the switching from the current channel to the new
channel and the regulatory maximum transmit power in the new
channel. For example, the channel power management mode field 530,
740 of the frame 1240 includes a value set to `4` or `5`, and the
regulatory maximum transmit power field 570, 780 includes a value
set to 40 mW of the regulatory maximum transmit power.
[0146] Thereafter, referring to FIG. 15, the stations 1203, 1205,
and 1207 obtain information on the new channel by using the frame
1240 received from the AP 1201.
[0147] That is, the stations 1203, 1205, and 1207 may identify not
the power switching but the switching to the new channel by
analyzing the channel power management mode field of the received
frame 1240. Further, the stations 1203, 1205, and 1207 may identify
the available maximum transmit power in the new channel by
analyzing the regulatory maximum transmit power field.
[0148] When the receiving processes of the stations 1203, 1205, and
1207 are completed, the AP 1201 and the stations 1203, 1205, and
1207 belonging to the wireless network start communication again in
the new channel (channel 21) by using the maximum transmit power of
40 mW.
[0149] FIG. 16 illustrates a process flow of performing power
switching or channel switching by devices belonging to a wireless
network by using the information element or frame according to the
present invention.
[0150] Referring to FIG. 16, in step 1601, an AP and stations
belonging to the wireless network perform communication by using a
specific TVWS channel.
[0151] While the communication is performed by using the specific
TVWS channel, a TV signal may appear in an adjacent channel to the
specific TVWS channel. In this case, in order to prevent
interference on the TV signal, the AP needs to announce the
regulatory maximum transmit power in the operating channel.
[0152] Further, while the communication is performed by using the
specific TVWS channel, a TV signal may appear in this channel. In
this case, the AP needs to announce switching from the current
channel to a new channel and the regulatory maximum transmit power
in the new channel.
[0153] In step 1603, the stations receive, from the AP, a frame
including a channel power management announcement element or an
additional channel power management announcement frame. When the
receiving the frame is completed, next step 1605 is performed.
[0154] In step 1605, the stations analyze the channel power
management mode field of the received frame. Here, the channel
power management mode field performs signaling to indicate whether
a role of the frame is to switch transmit power on the operating
channel or to switch channels.
[0155] In step 1607, the stations determine whether the channel
power management mode field indicates channel switching on the
basis of a result of the analysis in step 1605. When the result
indicates not the channel switching but the power switching in the
operating channel, step 1609 is performed.
[0156] In step 1609, the stations analyze the regulatory maximum
transmit power field of the received frame. Thereafter, in step
1611, it, is determined whether the regulatory maximum transmit
power in the operating channel is 40 mW on the basis of a result of
the analysis on the field.
[0157] When the regulatory maximum transmit power is 40 mW, step
1613 is performed. In step 1613, the devices belonging to the
wireless network start communication again in the current channel
with the maximum transmit power of 40 mW. When the regulatory
maximum transmit power is 100 mW, step 1615 is performed. In step
1615, the devices belonging to the wireless network start
communication again in the current channel with the maximum
transmit power of 100 mW.
[0158] When it is determined that the channel power management mode
field indicates the channel switching in step 1607, step 1617
performed.
[0159] In step 1617, the stations analyze the operating class and
channel number fields of the received frame. By analyzing the
fields, the stations may identify the channel number and channel
bandwidth of a channel to move to.
[0160] In step 1619, the stations analyze the regulatory maximum
transmit power field of the received frame. By analyzing the field,
the stations may identify the available maximum transmit power in a
channel to move to.
[0161] In step 1621, the stations move to a new channel from the
current channel on the basis of a result of the analysis on the
operating class and channel number fields.
[0162] Thereafter, in step 1623, the stations determine whether the
regulatory maximum transmit power is 40 mW on the basis of a result
of the analysis on the regulatory maximum transmit power field.
[0163] When the regulatory maximum transmit power is 40 mW, step
1625 is performed. In step 1625, the devices belonging to the
wireless network start communication in the new channel with the
maximum transmit power of 40 mW.
[0164] When the regulatory maximum transmit power is 100 mW, step
1627 is performed. In step 1627, the devices belonging to the
wireless network start communication in the new channel with the
maximum transmit power of 100 mW.
[0165] As described above, according to the first embodiment, the
wireless LAN devices are enabled to identify information on
available maximum transmit power in an operating channel or a
channel to move to by using a newly defined information element or
frame.
[0166] Further, by virtue of the identifying the channel
information, the wireless LAN devices may change the maximum
transmit power according to whether a TV signal exists in an
adjacent channel to thereby prevent interference on the TV
channel.
Second Embodiment
[0167] According to the regulations of the FCC, a wireless LAN
device capable of accessing a geo-location data, from among
wireless LAN devices operating in the TVWS, may enable other
devices so as to configure a network.
[0168] In the case of using the FCC regulations and the dynamic
station enablement (DSE) defined in the IEEE 802.11y standard, the
wireless LAN device capable of accessing the geo-location database
may be an enabling station (hereinafter, referred to as an enabling
STA). This enabling STA may approve enablement of available
channels for dependent stations (hereinafter, referred to as
dependent STAs).
[0169] Here, the enabling STA may enable a plurality of TVWS
channels for the dependent STAs on the basis of the available
channel list obtained from the geo-location database. However, when
the available channel list of the geo-location database is changed
later, or when a primary user is detected according to a sensing
result report from peripheral stations, the enabling STA needs to
perform deenablement to a specific channel.
[0170] However, the IEEE 802.11y or IEEE 802.11af standard does not
provide a deenablement method for a specific channel. Therefore, a
second embodiment provides a method for enabling wireless LAN
devices operating in the TVWS to perform deenablement for each
channel according to whether a primary user (or TV signal
exists.
[0171] Hereinafter, the second embodiment will be described in
detail with reference to the accompanying drawings.
[0172] FIG. 17 illustrates an example of performing enablement by
the enabling STA and dependent STA operating in the TVWS.
[0173] Referring to FIG. 17, a wireless LAN device capable of
accessing a geo-location database (DB) 1710 may become an enabling
STA 1720 to perform an enablement process.
[0174] Here, the enabling STA 1720 includes location information
thereof, and thus may obtain an available channel list 1740 for a
corresponding location by accessing the geo-location database 1710.
In the present embodiment, it is assumed that available channels of
the available channel list are channels 21 to 23.
[0175] Thereafter, the dependent STA 1730 transmits a DSE
enablement request frame 1750 to the enabling STA 1720.
[0176] Then, the enabling STA 1720 transmits a DSE enablement
response frame 1760 corresponding to the DSE enablement request
frame 1750 to the dependent STA 1730. That is, the enabling STA
1720 approves the enablement request by transmitting the DSE
enablement response frame 1760.
[0177] Here, the DSE enablement frame defined in the IEEE 802.11y
standard may be used for the DSE enablement request frame 1750
transmitted by the dependent STA 1730 and the DSE enablement
response frame 1760 transmitted by the enabling STA 1720. In the
present embodiment, it is assumed that the enabling STA 1720
approves operating of the dependent STA 1730 in channels 21 to
23.
[0178] The dependent STA 1730 selects one of the TVWS channels
approved by the enabling STA 1720 in order to operate. In the
present embodiment, it is assumed that the dependent STA 1730
selects the channel 22 in order to operate.
[0179] When the above-described enablement process is successfully
completed, the dependent STA 1730 is associated with the enabling
STA 1720 so as to start a wireless network operation.
[0180] FIG. 18 illustrates an example of performing deenablement by
the enabling STA and dependent STA of FIG. 17.
[0181] Referring to FIG. 18, the enabling STA 1720 may periodically
access the geo-location database 1720 to update the available
channel list. For example, the enabling STA 1720 may access the
geo-location database 1720 at predetermined time intervals to
update the available channel list.
[0182] In the present embodiment, it is assumed that the channels
21 and 23 are updated. That is, it is assumed that the channel 22
that is currently operating in the wireless network is no more
available due to appearance of a primary user (or TV signal).
[0183] Since the operating channel is no more available due to the
primary user, the enabling STA 1720 deenables the dependent STA
1730, for which enablement has been approved by the enabling STA
1720, from operating in the channel 22. Here, the enabling STA 1720
requests deenablement for a specific channel by using a DSE
extended deenablement frame 1820.
[0184] The DSE extended deenablement frame 1820 is newly defined in
order to overcome a problem of the DSE deenablement public action
frame defined in the IEEE 802.11y standard, i.e. a problem of
inability to perform deenablement for a specific channel.
Hereinafter, the DSE deenablement public action frame defined in
the IEEE 802.11y and the DSE extended deenablement frame proposed
by the present invention will be described in detail.
[0185] FIG. 19 illustrates a structure of the DSE deenablement
public action frame defined in the IEEE 802.11y.
[0186] Referring to FIG. 19, the DSE deenablement public action
frame 1900 includes a category field 1910, a public action field
1920, a requester STA address field 1930, a responder STA address
field 1940, and a reason result code field 1950.
[0187] The category field 1910 represents a category of the
corresponding frame, and the public action field 1920 represents
that the corresponding frame is the DSE deenablement frame.
[0188] The requester STA address field 1930 represents a media
access control (MAC) address of a station requesting deenablement.
Here, a length of the requester STA address field 1930 is 6
octets.
[0189] The responder STA address field 1940 represents a MAC
address of a station deenabled. Here, a length of the responder STA
address field 1940 is 6 octets.
[0190] The reason result code field 1950 is used to represent a
reason why the DSE deenablement frame 1900 is generated. According
to this generation reason, one of the field values shown in FIG. 19
may be allocated.
[0191] For example, when the enabling STA sets a value of the
reason result code field 1950 of the DSE deenablement frame 1900 to
`2`, this value indicates that the frame 1900 has been generated to
request deenablement.
[0192] FIG. 20 illustrates a structure of the DSE extended
deenablement frame according to the second embodiment.
[0193] Referring to FIG. 20, the DSE extended deenablement frame
2000 includes a category field 2010, a public action field 2020, a
requester STA address field 2030, a responder STA address field
2040, a reason result code field 2050, a length field 2060, an
operating class field 2070, and a channel number field 2080.
[0194] The category field 2010 represents a category of the
corresponding frame, and the public action field 2020 represents
that the corresponding frame is the DSE extended deenablement
frame.
[0195] The requester STA address field 2030 represents a media
access control (MAC) address of a station requesting deenablement.
Here, a length of the requester STA address field 2030 is 6
octets.
[0196] The responder STA address field 2040 represents a MAC
address of a station deenabled. Here, a length of the responder STA
address field 2040 is 6 octets.
[0197] The reason result code field 2050 is used to represent a
reason why the DSE extended deenablement frame 2000 is generated.
According to this generation reason, one of the field values shown
in FIG. 20 may be allocated.
[0198] For example, when the enabling STA sets a value of the
reason result code field 2050 of the DSE extended deenablement
frame 2000 to `2`, this value indicates that the frame 2000 has
been generated to request deenablement.
[0199] When the enabling STA sets a value of the reason result code
field 2050 of the DSE extended deenablement frame 2000 to `3`, this
value indicates that the frame 2000 has been generated to request
deenablement for a specific channel.
[0200] The length field 2060 represents lengths of the operating
class field 2070 and channel number field 2080. Therefore, the
operating class field 2070 and channel number field 2090 may be
repeated by as much as the length specified in the length field
2060. The operating class field and channel number field 2090 may
be repeated by as much as the number of channels. The value of the
length field 2060 may be variable, and a minimum value thereof is
1.
[0201] The operating class field 2070 represents a number of an
operating class of a channel for which deenablement is requested.
The channel number field 2080 represents a number of the channel
for which deenablement is requested.
[0202] In particular, the length field 2060, the operating class
field 2070, and the channel number field 2080 exist only when the
value of the reason result code field 2050 is set to `3`.
[0203] Referring to FIG. 18, the enabling STA 1720 transmits, to
the dependent STA 1730, the DSE extended deenablement frame 2000 in
which the reason result code field 2050 is set to `3` and the
channel number field 2080 is set to `channel 22` in order to
request deenablement for the channel 22.
[0204] Then, the dependent STA 1730 accepts the request and stops
operating at the channel 22 where the dependent STA 1730 is
operating.
[0205] As described above, the enabling STA 1720 may perform
deenablement for a specific channel by using the DSE extended
deenablement frame 2000 proposed by the present invention.
[0206] FIG. 21 illustrates another example of performing
deenablement by the enabling STA and dependent STA of FIG. 17.
[0207] Referring to FIG. 21, the dependent STA 1730 detects a
primary user (or TV signal) by means of spectrum sensing. For
example, the dependent STA 1730 performs the spectrum sensing at
predetermined intervals to detect a TV signal in currently
operating channel 22.
[0208] Thereafter, the dependent STA 1730 reports that the TV
signal is detected in the channel 22 to the enabling STA 1720.
Here, the dependent STA 1730 reports by using the radio measurement
report frame defined in the IEEE 802.11k standard.
[0209] The enabling STA 1720 receives the radio measurement report
frame to recognize that the TV signal is detected in the channel
22. Thereafter, the enabling STA 1720 deenables the dependent STA
1730, for which enablement has been approved by the enabling STA
1720, from operating in the channel 22.
[0210] Here, the enabling STA 1720 performs deenablement for a
specific channel by using the above-described DSE extended
deenablement frame 2000.
[0211] More specifically, the enabling STA 1720 transmits, to the
dependent STA 1730, the DSE extended deenablement frame 2000 in
which the reason result code field 2050 is set to `3` and the
channel number field 2080 is set to `channel 22` in order to
request deenablement for the channel 22.
[0212] Then, the dependent STA 1730 accepts the request and stops
operating at the channel 22 where the dependent STA 1730 is
operating.
[0213] As described above, the enabling STA 1720 may perform
deenablement for a specific channel by using the DSE extended
deenablement frame 2000 proposed by the present invention.
[0214] FIG. 22 illustrates a process flow of performing
deenablement to the dependent STA by the enabling STA using the DSE
extended deenablement frame.
[0215] Referring to FIG. 22, in step 2201, the dependent STA
selects one from TVWS channels, for which enablement has been
approved by the enabling STA, in order to initiate an
operation.
[0216] In step 2203, the dependent STA receives the DSE extended
deenablement frame from the enabling STA.
[0217] The enabling STA transmits the DSE extended deenablement
frame when an updated available channel list is obtained or when a
radio measurement report frame reporting that a primary user is
detected in an enablement-approved channel is received.
[0218] In step 2205, the dependent STA analyzes the requester STA
address field of the DSE extended deenablement frame. Thereafter,
in step 2207, the dependent STA confirms whether an address of a
requesting station matches an address of the enabling STA.
[0219] When the addresses do not match each other, the process flow
moves to step 2201 in order to perform a wireless network
operation. When the addresses match each other, the process flow
moves to next step 2209.
[0220] In step 2209, the dependent STA analyzes the responder STA
address field of the DSE extended deenablement frame. Thereafter,
in step 2211, the dependent STA confirms whether an address of a
responding station matches an address of the dependent STA.
[0221] When the addresses do not match each other, the process flow
moves to step 2201 in order to perform a wireless network
operation. When the addresses match each other, the process flow
moves to next step 2213.
[0222] In step 2213, the dependent STA analyzes the reason result
code field of the DSE extended deenablement frame.
[0223] Thereafter, in step 2215, the dependent STA confirms whether
there is a field value indicating a deenablement request. Here,
when the value of the reason result code field is set to `2`, this
value indicates that the corresponding frame has been generated to
request deenablement. When the value of the reason result code
field is set to `3`, this value indicates that the corresponding
frame has been generated to request deenablement for a specific
channel.
[0224] When it is confirmed that the value of the reason result
code field is set to `2`, the process flow moves to next step 2221.
In step 2221, the dependent STA is deenabled and stops operating
for all channels.
[0225] When it is confirmed that the value of the reason result
code field is set to `3`, the process flow moves to next step 2217.
In step 2217, the dependent STA analyzes the operating class field
and channel number field of the DSE extended deenablement
frame.
[0226] Thereafter, in step 2219, the dependent STA confirms whether
the operating class and channel number of the received frame match
the operating channel of the dependent STA. When the operating
class and channel number do not match the operating channel, the
process flow moves to step 2201 in order to perform a wireless
network operation.
[0227] When the operating class and channel number match the
operating channel, the process flow moves to next step 2221. In
step 2221, the dependent STA is deenabled and stops operating for a
specific channel.
[0228] As described above, according to the second embodiment, the
enabling STA operating in the TVWS may deenable the dependent STA
with respect to a specific channel or all channels.
[0229] FIG. 23 is a block diagram illustrating wireless LAN devices
in which the embodiments may be implemented.
[0230] Referring to FIG. 23, the wireless LAN devices include an AP
2300 and a station 2350. Each of the AP 2300 and station 2350
includes a control unit 2305 or 2355, an RF transmitting/receiving
unit 2310 or 2360, a PHY unit 2315 or 2375, and a MAC unit 2320 or
2370. The AP 2300 may further include a channel management unit
2325, an IP protocol unit 2330, and a location identifying unit
2335.
[0231] The RF transmitting/receiving unit 2310 or 2360 serves to
convert a signal inputted from the PHY unit 2315 or 2375 that is a
physical layer into an RF signal, and then transmit the converted
signal via an antenna after filtering and amplifying the converted
signal.
[0232] The RF transmitting/receiving unit 2310 or 2360 converts the
RF signal received from the antenna into a signal that can be
processed in the PHY unit 2315 or 2375 by performing a filtering
operation. The RF transmitting/receiving unit 2310 or 2360 may have
a switch function for switching between transmission and reception
of the signal.
[0233] The PHY unit 2315 or 2375 performs forward error correction
(FEC) encoding and modulation to data requested to be transmitted
from the MAC unit 2320 or 2370 that is a media access control (MAC)
layer, and performs a process of adding signals such as a preamble
and a pilot to transmit the processed data to the RF
transmitting/receiving unit 2310 or 2360.
[0234] The PHY unit 2315 or 2375 performs demodulation,
equalization, and FEC decoding to the signal received via the RF
transmitting/receiving unit 2310 or 2360, and performs a process of
removing the added preamble and pilot to transmit the processed
signal to the MAC unit 2320 or 2370. For these operations, the PHY
unit 2315 or 2375 may include a modulator, a demodulator, an
equalizer, a FEC encoder, and a FEC decoder.
[0235] The MAC unit 2320 or 2370 processes data transferred from an
upper layer, i.e. the data requested to be transmitted, and then
outputs the processed data to the PHY unit 2315 or 2375 and
performs additional transmission for transferring the data.
[0236] The MAC unit 2320 or 2370 processes received data inputted
from the PHY unit 2315 or 2375 to transmit the processed data to an
upper layer, and performs additional transmission for transferring
the data.
[0237] The IP protocol unit 2330 processes data inputted from an
upper layer to transmit the processed data to the MAC unit 2320 or
2370, and processes data inputted from the MAC unit 2320 or 2370 to
transmit the processed data to an upper layer.
[0238] The location identifying unit 2335 performs an operation for
confirming a location thereof. The channel management unit 2325
accesses a geo-location database by using information on the
location confirmed by the location identifying unit 2235, and
obtains a list of TVWS channels that are available at the location.
The channel management unit 2325 selects at least one channel from
the obtained TVWS channel list and performs an operation for
initiating a wireless network in the channel.
[0239] The control unit 2305 or 2355 controls the RF
transmitting/receiving unit 2310 or 2360, the PHY unit 2315 or
2375, and the MAC unit 2320 or 2370 in response to a control signal
transmitted from an upper layer. The control unit 2305 or 2355
performs various adjusting and managing operations so as to control
requests and processing time points among the RF
transmitting/receiving unit 2310 or 2370, the PHY unit 2315 or
2375, and the MAC unit 2320 or 2370.
[0240] Further, the control unit 2305 or 2355 controls an operation
for performing the channel information identifying method according
to the first embodiment. For example, the control unit 2305 of the
AP 2300 may control an overall process of generating and signaling
a frame including information on an operating class, a channel
number, and regulatory maximum transmit power. The control unit
2355 of the station 2350 may control an overall process of
analyzing a frame received from the AP 2300 and identifying channel
information.
[0241] Hereinafter, an operation of identifying channel information
through a process of signaling between the AP 2300 and the station
2350 will be described in detail.
[0242] The AP 2300 may detect that a TV signal appears in an
operating channel or an adjacent channel thereto on the basis of
periodically updated available channel list information or a result
of spectrum sensing. Here, the control unit 2305 generates the
channel power management announcement frame 700 in order to
announce power switching in an operating channel or a new channel.
Further, the control unit 2305 may generate a beacon frame or probe
response frame including the channel power management announcement
element 500 instead of generating an additional frame.
[0243] That is, the control unit 2305 may control the MAC unit 2320
and the PHY unit 2315 so as to generate the channel power
management announcement frame. Here, the channel power management
announcement frame generated by the control unit 2305 includes
information on a channel power management mode, an operating class,
a channel number, and regulatory maximum transmit power.
[0244] The MAC unit 2320 processes data transferred from an upper
layer, i.e. the data requested to be transmitted, and then outputs
the processed data to the PHY unit 2315 in response to control by
the control unit 2305. Here, the data includes information on a
channel power management mode, an operating class, a channel
number, and regulatory maximum transmit power.
[0245] The PHY unit 2315 performs forward error correction (FEC)
encoding and modulation to data requested to be transmitted from
the MAC unit 2320 that is a media access control (MAC) layer. Then,
the PHY unit 2315 performs a process of adding signals such as a
preamble and a pilot to the modulated signal so as to generate a
frame and transmits the generated frame to the RF
transmitting/receiving unit 2310.
[0246] The RF transmitting/receiving unit 2310 converts a frame
inputted from the PHY unit 2315 that is a physical layer into an RF
signal, and then transmits the converted frame via an antenna after
filtering and amplifying the converted frame. Here, the frame
transmitted via the antenna is the channel power management
announcement frame 700.
[0247] The station 2350 may receive the channel power management
announcement frame including channel information from the AP
2300.
[0248] That is, the RF transmitting/receiving unit 2360 converts
the RF signal received via the antenna into a digital signal that
can be processed in the PHY unit 2365 by performing a filtering
operation.
[0249] The PHY unit 2365 performs demodulation, equalization, and
FEC decoding to the frame received via the RF
transmitting/receiving unit 2360, and performs a process of
removing the added preamble and pilot to output a data bit.
Thereafter, the PHY unit 2365 transmits the outputted data bit to
the MAC unit 2370.
[0250] The MAC unit 2370 processes received data inputted from the
PHY unit 2365 to transmit the processed data to an upper layer.
Here, the data includes information on a channel power management
mode, an operating class, a channel number, and regulatory maximum
transmit power.
[0251] The control unit 2355 may control the MAC unit 2370, the PHY
unit 2365, and the RF transmitting/receiving unit 2360 so as to
obtain corresponding information from the channel power management
announcement frame. That is, the control unit 2355 may identify
information on power switch in a current channel by analyzing the
received channel power management announcement frame. Further, the
control unit 2355 may identify information on switch to a new
channel and power switch in the new channel by analyzing the
received channel power management announcement frame.
[0252] Further, the control unit 2305 or 2355 controls an operation
for performing deenablement according to the second embodiment. In
the present embodiment, the enabling STA may be configured with the
same devices as the AP 2300, and the dependent STA may be
configured with the same devices as the station 2350.
[0253] The control unit 2305 of the enabling STA 2300 may control
an overall process of generating and signaling a frame including
information on an operating class, a channel number, and
deenablement. The control unit 2355 of the dependent STA 2350 may
control an overall process of analyzing a frame received from the
enabling STA 2300 and performing deenablement.
[0254] The enabling STA 2300 may recognize that a primary user is
detected in an enablement-approved channel on the basis of an
updated available channel list. Further, the enabling STA 2300 may
receive a radio measurement report frame transmitted from the
dependent STA 2350 to recognize that a primary user is detected in
an enablement-approved channel. Here, the enabling STA 2300
generates the DSE extended deenablement frame 200 in order to
perform deenablement for the corresponding channel.
[0255] That is, the control unit 2305 may control the MAC unit 2320
and the PHY unit 2315 so as to generate the DSE extended
deenablement frame 2000. Here, the DSE extended deenablement frame
2000 generated by the control unit 2305 includes information on an
operating class, a channel number, and a deenablement reason.
[0256] The MAC unit 2320 processes data transferred from an upper
layer, i.e. the data requested to be transmitted, and then outputs
the processed data to the PHY unit 2315 in response to control by
the control unit 2305. Here, the data includes information on an
address of a requesting station, an address of a responding
station, an operating class, a channel number, and a deenablement
reason.
[0257] The PHY unit 2315 performs forward error correction (FEC)
encoding and modulation to data requested to be transmitted from
the MAC unit 2320 that is a media access control (MAC) layer. Then,
the PHY unit 2315 performs a process of adding signals such as a
preamble and a pilot to the modulated signal so as to generate a
frame and transmits the generated frame to the RF
transmitting/receiving unit 2310.
[0258] The RF transmitting/receiving unit 2310 converts a frame
inputted from the PHY unit 2315 that is a physical layer into an RF
signal, and then transmits the converted frame via an antenna after
filtering and amplifying the converted frame. Here, the frame
transmitted via the antenna is the DSE extended deenablement
frame.
[0259] The dependent STA 2350 may receive the DSE extended
deenablement frame 2000 from the enabling STA 2300.
[0260] That is, the RF transmitting/receiving unit 2360 converts
the RF signal received via the antenna into a digital signal that
can be processed in the PHY unit 2365 by performing a filtering
operation.
[0261] The PHY unit 2365 performs demodulation, equalization, and
FEC decoding to the frame 2000 received via the RF
transmitting/receiving unit 2360, and performs a process of
removing the added preamble and pilot to output a data bit.
Thereafter, the PHY unit 2365 transmits the outputted data bit to
the MAC unit 2370.
[0262] The MAC unit 2370 processes received data inputted from the
PHY unit 2365 to transmit the processed data to an upper layer.
Here, the data includes information on an address of a requesting
station, an address of a responding station, an operating class, a
channel number, and a deenablement reason.
[0263] The control unit 2355 may control the MAC unit 2370, the PHY
unit 2365, and the RF transmitting/receiving unit 2360 so as to
obtain corresponding information from the DSE extended deenablement
frame 2000.
[0264] That is, the control unit 2355 analyzes the requester STA
address field of the DSE extended deenablement frame in order to
confirm whether an address of a requesting station matches that of
the enabling STA 2300: Further, the control unit 2355 analyzes the
responder STA address field of the DSE extended deenablement frame
in order to confirm whether an address of a responding station
matches that of the control unit.
[0265] Further, the control unit 2355 analyzes the reason result
code field of the DSE extended deenablement frame in order to
confirm whether deenablement is performed for a specific channel or
all channels.
[0266] According to a result of the confirmation, the control unit
2355 may perform deenablement for a specific channel or all
channels.
[0267] At least a part of the methods according to the embodiments
may be implemented as a program to be executed in a computer and
may be stored in a computer-readable recording medium. The
computer-readable recording medium includes a ROM, a RAM, a CD-ROM,
a magnetic tape, a floppy disk, and an optical data storage device.
Further, the methods may also be implemented as a form of a carrier
wave (for example, transmission via the Internet).
[0268] The computer-readable recording medium may be distributed to
computer systems connected to a network so that computer-readable
codes may be stored and executed in a distribution manner. Further,
a function program, a code, and code segments for implementing the
methods may be easily derived by programmers skilled in the
technical field to which the present invention belongs.
[0269] Although embodiments have been described with reference to a
number of illustrative embodiments thereof, numerous other
modifications can be devised without departing from the scope of
the present disclosure. Therefore, the scope of the present
disclosure is not limited to the described embodiments but should
be determined by the following claims and their equivalents.
[0270] That is, the above detailed description shows an example
applied to a wireless LAN system using the TV white space. However,
the present disclosure can also be applied to other wireless
communication systems using the TV white space by those skilled in
the art without departing the scope of the present disclosure.
* * * * *